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Transcript
NAME: ______________________________________ DATE: ____________ BLOCK: ____ Evolution - ___________________________ over generations Organisms change over time – this is a fact. How organisms have changed throughout earth’s history is theory. EVIDENCE OF EVOLUTION ____________________________ Comparative anatomy Embryology ____________________________ Genetics Direct observation FOSSILS Fossils - a __________________ of an organism that lived long ago Fossil records- use radiometric dating or rock layers to date fossils Fossil records are incomplete: o soft tissues o weather Geographic distribution of species o Similar organisms in different areas Fossils of extinct organisms COMPARATIVE ANATOMY Comparative anatomy- the study of structures of different organisms Homologous structures - __________________________________ modified between different organisms o The more similar the structures, the closer the relationship between two organisms o Example: a bat’s wing, a horse’s leg and a human forearm Vestigial Organs - structures that have _____________________________ in present organisms, but may have been used in ancestors Example in animals o pelvic bone in some snakes and whales Examples of Vestigial Organs in Humans o _________________________________ o wisdom teeth o _________________________________ o pointed canines 1 EMBRYOLOGY Comparative embryology - the study of embryos (early stages of life) of different organisms o The more similar the embryos, the more closely related two organism are o ex. human and pig embryos appear very ________________________ to each other BIOCHEMISTRY and GENETICS Chemicals (like proteins, DNA, mRNA etc) in different organisms show similarities. More similar chemicals means more closely related Example- Hemoglobin in chimpanzees is very similar to hemoglobin in humans GENETICS How are offspring genetically different from their parents? In other words, how can evolution occur from one generation to the next? o Meiosis – remember, individuals can make lots of genetically different sex cells o Mutations – DNA can change! o Sex – combines two individuals’ DNA together DNA sequences of all living things have many similarities Base sequences of DNA o DNA of humans and chimpanzees is ___________ identical o DNA of humans and other mammals is ___________ identical DIRECT OBSERVATION Direct observation - evolutionary changes are happening ____________ o Example - bacteria becoming resistant to antibiotics CHARLES DARWIN Charles Darwin – an Englishman credited for first describing natural selection o HMS Beagle – a British survey _______________on which Darwin was a naturalist. This ship sailed around the world in 1831. Galapagos Islands – located 600 miles west of South America. The islands have very different climates and thus the organisms adapt according to the environment. o Giant tortoise, marine iguanas, and finches vary from island to island due to different environments Artificial Selection – __________ chose particular species to breed (selective breeding) o Artificial selection helped to explain that variations in species could make them better adapted. o Dog breeders, farmers, gardeners have been using artificial selection for years. 2 NATURAL SELECTION The _____________________________of the _________________________________ Darwin wondered why there were so many different species of finches on the Galapagos Islands. He proposed the concept of natural selection. Natural Selection - the __________________________________ individuals in a population survive and reproduce offspring that are also well adapted The least adapted produce fewer offspring and are less likely to survive. Among the various traits that _____________________, certain traits may benefit a population The environment typically does _____________cause the variation! o Examples Virus from outer space – kills blue-eyed people (but does not change a person’s eyes to blue) Spadefoot toad – must bury itself in the ground and mate quickly when it comes to the surface, therefore, it has a loud croak and long toes! TYPES OF SELECTION Directional Selection – when individuals at one ___________ of the curve have higher fitness than individuals in the middle. o Example: birds with larger beaks are better able to survive food shortages than those with small and medium beaks Stabilizing Selection - when individuals at ______________ of the curve have higher fitness than individuals at the ends. o Example: average-sized babies are most likely to survive compared to really big and really small babies Disruptive selection - when individuals at _____________________ of the curve have higher fitness than individuals in the middle. o Example: due to small and large seeds, birds with small and large beaks are most fit compared to birds with medium beaks Some vocab… Gene Pool - the entire collection of genes among a _____________________________ Population - All organisms within a breeding group (same species) Gene Frequency - The _____________________________ an allele appears in a gene pool ______________ in gene ________________ mean that the population has evolved. An entire population evolves, not an individual! A specific gene may be “selected” for by the environment. GENETIC DRIFT Genetic Drift - _______________ changes in gene frequency of a _____________, ___________ population o Ex. in small populations, a recessive allele can become much more common 3 o In the Amish population, certain genetic disorders are more common than in the general population. ADAPTATIONS Adaptations - _____________________________ of a living organism that help it to survive in its environment Adaptations evolve by ______________________________! TYPES OF ADAPTATIONS ________________________ - physical parts o Ex. woodpecker’s tongue, anglerfish, anteater’s snout, hummingbird’s beak ________________________ - chemicals made by organisms o Ex. poison venom of a snake, ink of a squid ________________________ o Ex. migration of birds, mating dances TYPES OF EVOLUTION Convergent Evolution – species that are _______closely related evolve similar traits (two species look like they are closely related and they are not) o Example: dolphins (mammals) and sharks (fish) Divergent evolution – one species evolves into two or more species with __________________ characteristics (speciation) o Example: lions and tigers evolved from a common ancestor SPECIATION Speciation – _________________ of two different _____________________ from one common ancestor. What keeps two species apart so that they evolve differently? Isolating mechanisms – keep groups apart o Geographic Isolation – ______________ changes occur that isolate individuals of a population Ex. Squirrels separated by Grand Canyon and Darwin’s finches separated by being on different islands o Genetic Isolation – genes don’t mix right Donkeys and horses make mules, but mules are sterile. o Temporal isolation – timings off Different species of skunks that mate at different times of the year. o Behavioral isolation – behaviors don’t match Certain species of lightning bugs use different blinking patterns to attract mates. THEORY OF ORIGIN OF LIFE Theory - a major hypothesis that has withstood the test of time o Based on observations and evidence o The closest to a complete explanation that science can offer 4 ORIGINAL ATMOSPHERE Hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water. __________________________ gas FIRST ORGANISMS Prokaryotes [__________________] - first cells; have genetic material (RNA or DNA); starting 3.5 byaFirst prokaryotes First prokaryotes were __________________________(eat food) Later, some bacteria became ____________________________(make own food) o Chemosynthesis - using energy from chemicals to make food o Photosynthesis - using CO2 and light to make food Cyanobacteria put ___________________________ in atmosphere. Oxygen drove some life forms to extinction, while other life forms evolved new ways to use oxygen (_______________respiration) Oxygen formed ____________________________- shielded earth from harmful UV and allowed an explosion of life (2.7 bya) Big steps… Eukaryotes (cells with nuclei) about 2.2 bya Plants and animals begin in water ____________________ and sexual reproduction in plants and animals o Increased genetic diversity _______________ and later ____________________ colonize land around 4.5 mya. First ____________________ and then first ______________________ (245 mya) Dinosaurs go extinct around 65 mya and this allows for evolution of larger mammals. Extinctions are often followed by explosions of new life forms! Remember your eras: Precambrium. Paleozoic, Mesozoic, and Cenozoic. HUMAN EVOLUTION Did man come from monkey??? o NO! Humans and monkeys evolved from a ____________________________ that lived approximately 65 million years ago and was a tree dweller (roughly the size of a cat). This was not a monkey like the monkeys today. Evolution of Primates Anthropoids developed into 3 groups: o New World Monkeys – includes squirrel and spider monkeys; have prehensile tail (can coil around branches) and lived in trees; found in central and S. America o Old World Monkeys – include giant apes, baboons, and macaques; do not have prehensile tail, but spend a lot of time in trees; found in Africa and Asia o Hominoids (great apes) – include orangutans, _________________, __________________, and ______________________ 5 HOMINIDS Hominid family includes modern humans and several distinctly different extinct species Bipedal – ____________________ locomotion o Freed hands to use tools Opposable thumb – allowed hand to _____________________ objects and tools Increased ___________________________ Australopithecus afarensis Very small brain capacity ~3.9-3.0 million years ago (mya) “________________” Bipedal apes that spent some time in trees ____________________ (Lucy is 1m) Homo habilis “_________________ man” ~2.5 mya Increased brain size Began to make and use _______________ 1.3 meters tall (4 feet tall) Homo erectus “__________________ man” ~ 1.8 mya - 250,000 years ago Taller __________________brain capacity (comparable to modern humans) Built fires Migrated out of Africa into China and Asia Homo sapiens (“wise man”) Homo sapiens neanderthalis o _____________________________ o Overlapped in existence with modern humans o Heavier brow ridge o Slightly larger brain capacity than modern human o Lived ~200,000 – 30,000 years ago Homo sapiens sapiens o First arose in Africa around 100,000 years ago. o Lived with Neanderthals for ~50,000 years. o Tools, art, and buried dead with rituals o One group became __________________________(in Europe) ~40,000 years ago. o We are Homo sapiens sapiens 6